Manny could have been trained by other trainers and he would be pretty much as good as he is now IMO......I could be wrong....
IMO you are wrong, Roach has worked with a bunch of top guys for many many years. Alizio is spot on the money here. Fighters can feel when they are advancing their skills with a certain trainer. Roach wouldn't get the business he gets if he wasn't making a huge impact on the fighters game. He also wouldn't get return business from the same fighters again and again.
The guy is simply amazing, I watched a documentary/short film on him last year, the guy really knows his shit. Personally I think he hasn't quite grasped the concept of MMA striking yet, but this is probably due to stubbornness attached with traditional boxing vs MMA.